Valve-gear



2'Sheets -Sheet 2.

(No Model.)

M.N.PAGKARD.

VALVE GEAR. "No. 325,964. Patented Sept; 8, 1885 witmqooao l r I awumwoz 7 Q3313 akto mwq wa WWW J? UNITED STATES PATENT OFFICE.

'MonRniL N. PACKARD, or BALTIMORE, MARYLAND.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 325,964, datedSeptember 8, 1885. Application filed July 20, 1885. (No model.)

To all whom it may concern:

Be it known that I,.MORRILL N. PACKARD, a citizen of the United States,residing at Baltimore, State of Maryland, have invented certain new anduseful Improvements in Valve-Gear for Steam-Engines; and Ido herebydeclare the following to be a full, clear, and exact descriptionoftheinvention, such as will enable others skilled in the art to whichit appertains to make and use the same.

My invention relates to improvements in valve-gear for steam-engines;and it has for its object to provide a gear simple in construction,durable in use, and one which can be easily and cheaply manufactured.

The nature of the invention consists in the combination, with avalve-stem, ofa vibrating lever whose upper portion forms a link pivotedto the stem, and a fulcrum-block fitted in said link and adapted to bemoved by suitable actuating mechanism to positions above or below thepivotal point of the link for the purpose of changing the order of thelever and consequently changing the direction of movement of thevalve-stem with relation to that of the arm of the lever. I

Figure 1 of the drawings is a side view of my invention, showing thepreferred construction. Fig. 2 is a perspective view of the same. Fig. 3is a perspective View illustrating a modification. Fig. 4 is a sideviewof my improved valve-gear attached to'an engine.

Referring to the drawings,'A represents the valve-stem, having bearingin brackets to, at-

tached to any convenient part of the frame work of the engine.

Pivoted to the valve-stem, between the bracket-bearings a, is a leverfor actuating it, this lever comprising a link, B, and an arm, B. In theback of the link B is formed a guide-groove, b,'for the accommodation ofa fulcrum-block, which will be presently described. For the purpose ofmaking the link as light as possible, its face is cut out, as at b b,leaving a bridge-piece, b, by which to con nect the link with thevalve-stem.

Sliding in groove 12 in link B is a fulcrumblock, D, loosely attached toany suitable actuating mechanism. A preferable mechanism v for slidingthe fulcrum-block, and also for steadying it in its movements in bedescribed as follows:

the link, may

0 represents a guide, attached to any suitable part of the machine,inwhich guide is fitted a sliding guide-block, F. This guide-block isrigidly fixed on one end of a shaft, G, and on the other end of saidshaft is journaled the fulcrum-block. Shaft G, and consequently blocks Dand F, is raised and lowered by means of a lever, E, attached thereto,which .lever is pivoted, as at e, to the frame-work of the engine, andis connected at its inner end with any desired operating mechanism. Theguideway c in guide 0 is slightly curved, as shown, in order to conformto the arc of a circle described by the'guide-block in moving from oneposition to another. The corresponding are described by thefulcrum-block is compensated for by a slight movement of the valvestem.Ican, however, dispense entirely with guide 0, guide-block F, and shaftG by bending the end of lever E at a right angle and journaling thefulcrum-block thereon, as shown in Fig. 3.

In Fig. 4 I have shown my valve-gear applied to an engine, in order toclearly illustrate its operation, the inner end of lever E beingattached to a link, e, pivoted to an arm, 6'', on a rock-shaft, I. Tothis shaft is attached a lever, J, provided at its upper end with aspring-pawl for engagement with teeth in a toothed segment, K, wherebylever J and'the mechanism operated by it are held in any desiredposition. It is to be understood, of course, that the hereindescribedvalve-gear is to be applied to each side of the engine.

' Lever B B may derive its vibratory motion from the cross-head'of theengine, as seen in Fig. 4; but I do not wish to confine myself to theconstruction therein shown, as it will be at once apparent to themachinist that other means may be employed for actuating the lever-as,for instance, an eccentric on the driving-shaft.

As represented in Fig. 4, the lower end of arm .13 (which is preferablyflattened for the purpose) rests between friction-rolls h in thecross-head H, and as the piston-rod moves forward and backward itimparts movement to lever B B, and through the lever' to the valve-stem.

It will be observed that the movement of the valve-stem relatively tothat of the piston- 1 rod is governed by the position of the fulcrum-ICO block in link B, for when it is above the pi"- otal point I), asseen in Fig. 4, lever B B is of the second order, and therefore thevalvestem is moved in the same direction as the piston-rod. This,however, is changed when the fulcrum-block is drawn down to a positionbelow the pivotal point, for then the lever becomes one of the firstorder, and consequently the valve-stem is moved in a direction contraryto that of the piston-rod.

Lever E must be so regulated as not to permit the fulcrum-block to reachthe bottom of the guide-groove in link 13 when the latter is in avertical position, as seen in Fig. 1. This arrangement is renderednecessary by the fact that when lever B B is at the extreme limit of itsthrow in either direction the distance from its pivotal point to thecenter ofthe fulcrum-block is greater than when it occupies a verticalposition, and consequently allowance must be made for play of the linkon the block to compensate for this difference.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In a valve gear for steam-engines, the

. combination, with a valve-stem, ofa vibrating lever whose upperportion forms a link pivoted to the stem, and a fulcrum block fitted insaid link and adapted to be moved by suitable actuating mechanism topositions above or below the pivotal point of the link, substantially asdescribed, and for the purpose set forth.

2. The combination, with a crosshead and a valve-stem of a steam-engine,of a lever whose upper portion forms a link pivoted to the stem, and afulcrum-block fitted in said link and adapted to be moved by suitableactuating mechanism to positions above or below'the pivotal point of thelink, substantially as described, and for the purpose set forth.

3. The combination, with a cross-head and a valve-stem of asteam-engine, of a lever whose upper portion forms a link pivoted to thestem, a fulcrum-block fitted in said link, a guide secured to anysuitable part of the engine, a guide-block fitted to slide therein,

a shaft connecting the fulcrunrblock and the guide-block, and a leverfor actuating the shaft, substantially as described.

4. The combination, with a valve-stein of a steam engine, of a vibratinglever whose upper portion forms a link pivoted to the stem, afulcrum-block fitted in said link, and an actuating-lever on the end ofwhich the ful crum-block is journaled, in the manner and for the purposeset forth.

In testimony whereof I affiX my signature in presence of two witnesses.

MORRILL N. PACK ARD.

\Vitncsses:

JOHN T. ARMS, GEO. I. HILL.

